How to calculate the current of a 100 KVA transformer with a rating of 11kV/433V.

 

I = (KVA x 1000) / (√3 x V)

 

where:

I = current in amperes

KVA = apparent power rating of the transformer in kilovolt-amperes (100 KVA in this case)

V = rated voltage of the transformer (433V in this case)

√3 = square root of 3 (1.732)

 

For a 11kV/433V transformer, we need to determine the primary current and the secondary current separately.

 

Primary Current:

The primary voltage is 11kV. Assuming a three-phase connection, we can calculate the primary current as follows:

 

I1 = (KVA x 1000) / (√3 x V1)

where:

I1 = primary current in amperes

KVA = apparent power rating of the transformer in kilovolt-amperes (100 KVA in this case)

V1 = primary voltage of the transformer (11kV in this case)

√3 = square root of 3 (1.732)

 

Substituting these values in the formula, we get:

 

I1 = (100 x 1000) / (1.732 x 11000) = 5.46 amperes (approximately)

 

Therefore, the primary current of the 100 KVA transformer with a rating of 11kV/433V is approximately 5.46 amperes.

 

Secondary Current:

The secondary voltage is 433V. We can calculate the secondary current as follows:

 

I2 = (KVA x 1000) / (√3 x V2)

where:

I2 = secondary current in amperes

KVA = apparent power rating of the transformer in kilovolt-amperes (100 KVA in this case)

V2 = secondary voltage of the transformer (433V in this case)

√3 = square root of 3 (1.732)

 

Substituting these values in the formula, we get:

 

I2 = (100 x 1000) / (1.732 x 433) = 129.1 amperes (approximately)

 

Therefore, the secondary current of the 100 KVA transformer with a rating of 11kV/433V is approximately 129.1 amperes.

 

It's important to note that the actual current may vary depending on various factors such as the load, power factor, and other transformer characteristics.